1. Field of the Invention
The present invention relates to a dry carbon dioxide capturing apparatus, and more particularly, to a dry carbon dioxide (CO2) capturing device with improved energy efficiency, which includes utilizing a difference in temperature between separation of CO2 from an sorbent containing CO2 absorbed therein to regenerate the same (that is, CO2) and pre-treatment of allowing a recovery reactor to be in desired conditions such as proper temperature to regenerate CO2, to thereby achieve improvement of energy efficiency.
2. Description of the Related Art
A carbon dioxide capture apparatus in related art generally employs a wet process to recover CO2. That is, the wet process is carried out by passing CO2-containing gas through an amine solution, to allow CO2 to be absorbed into the solution and regenerating the solution in a regeneration column, thus reusing the solution. However, the wet process has a demerit of further creating waste water during operation of the wet process.
In order to overcome disadvantages of the wet process in the art, a dry process for CO2 recovery has been proposed. This method is to recover CO2 by a dry processing system using two reactors, wherein CO2 fed into a recovery reactor is adsorbed to a solid sorbent (a dry sorbent) and removed. The solid sorbent inflows into a regeneration reactor (‘regenerator’) to remove the adsorbed CO2, H2O is adsorbed to the solid sorbent in a pre-treatment reactor, and then the sorbent is recycled in a recovery reactor.
In this regard, in order to remove CO2 from the regenerator, an alternative heat source should be supplied. Also, the pre-treatment reactor must remove heat from the solid sorbent to ensure a temperature condition suitable to adsorb CO2 in the regenerator.
In related art, since a dry CO2 capturing device is commonly mounted in large-scale plants such as a power plant to generate CO2 in large quantities, steam generated in the power plant is generally used as a heat supplying medium while another medium for cooling may usually be water which is widely abundant.
However, the dry CO2 capturing device consumes a significant amount of calories, if the water with a highly elevated temperature in a large capacity plant after cooling is directly discharged to the outside, thermal contamination of water cannot be avoided due to adverse effects of hot waste water, which in turn has a negative influence upon aquatic species.